## To convert the given range of ridge systems from miles to kilometers, we can use the conversion factor that 1 mile is equal to approximately 1.609 kilometers.

First, let's convert the lower value of the range, which is 8 miles, to kilometers:

8 miles * 1.609 km/mile â‰ˆ 12.87 km

Next, let's convert the higher value of the range, which is 30 miles, to kilometers:

30 miles * 1.609 km/mile â‰ˆ 48.27 km

So, we can conclude that the range of ridge systems is approximately 12.87 km to 48.27 km wide.

Now, let's look at the given answer choices and find the option that is closest to the maximum width of 48.27 km:

- 10 km: This option is smaller than the maximum width of 48.27 km.

- 50 km: This option is closest to the maximum width of 48.27 km.

- 100 km: This option is larger than the maximum width of 48.27 km.

- 500 km: This option is larger than the maximum width of 48.27 km.

- 1000 km: This option is larger than the maximum width of 48.27 km.

Therefore, the closest option amongst the given choices is 50 km.